This invention relates to a cryogenic storage apparatus. More particularly, this invention relates to an apparatus for the preservation of biological specimens at or near the temperature of liquid nitrogen.
When properly treated, biological specimens can be stored almost indefinitely at temperatures approaching that of liquid nitrogen so long as that temperature is maintained. However, once the temperature of a specimen is raised, especially to a level where thawing occurs, the integrity of the specimen suffers if the specimen is then refrozen. Conventional devices for storing biological specimens at low temperatures are adequate for the storage of a group of samples, but if one or more samples are removed from the group, other samples may be exposed to thawing temperatures, with a resultant decrease in the viability of the refrozen cells.